In recent years, fiberoptic technology has revolutionized medical procedures. Nowhere have the advantages engendered by these advances been greater than in the area of surgical techniques. Due to their flexibility and relatively small size, surgical devices incorporating flexible light pipes (such as fiberoptics) may be inserted into bodily cavities through relatively small incisions, whereas prior to the advent of this technology, large incisions, and therefore major surgery was required for such access.
Fiberoptic surgical devices, once positioned within the bodily cavity, may be used to view body tissues contained within the cavity, and if properly adapted, to cut and remove undesired bodily tissue from the body cavity. It is often particularly useful for such fiberoptic cutting devices to use a coherent beam of electromagnetic radiation (e.g. a laser beam) to thermally damage undesired tissues. When struck by a low-power coherent beam, the undesired tissue may be cauterized and the tissue killed. Very often, one pulse of electromagnetic radiation may not be sufficient to destroy all of the undesired tissue. This may result in live, undesired tissue becoming covered by a layer of dead tissue. Disadvantageously, it may not be possible in such a situation, to destroy the underlying tissue without either increasing the strength of the coherent beam or providing some means for removing the dead tissues. Increasing the strength of the coherent beam may result in collateral damage to surrounding tissue. Additionally, the layer of dead tissues may prevent the surgeon from viewing the undesired underlying live tissue to be destroyed, and its presence thereby may go unnoticed.
Therefore, in light of the above problems, the prior art has proposed several fiberoptic surgical cutting tools capable of removing thermally damaged tissues. As will be presently seen, however, none of these devices are without serious drawbacks. For example, Hakky, U.S. Pat. No. 4,955,882, discloses a laser resectoscope with mechanical and laser cutting means for use in prostate surgery. The device disclosed by Hakky includes a rotating cutting element mounted within an outer sheath adapted to be inserted into the urethra. The cutting element contemplated by Hakky has helical threads along its length and a cutting blade at its distal end. Sheath means surround the cutting element except for the cutting blade. A fiberoptic laser filament for delivering laser energy to the issue site is positioned adjacent to the cutting blade. The laser filament is surrounded by a sheath and adapted to be moved by the rotation of the cutting element so that the laser beam emitted from the filament advances through the tissues to cut and coagulate the resected area before the cutting blade reaches them. Irrigation fluid is provided to the tissue site and ultrasound is used in conjunction with the laser resectoscope to plot the area of the prostate tissue to be removed. Computer control prevents cutting of tissue beyond the area of tissues desired to be removed.
Although providing somewhat effective means for removing undesired tissues after cauterization, Hakky's device is a single purpose surgical tool, i.e. for use in performing transurethrally prostate and/or bladder surgery. Also, Hakky's device, which employs a helical screw-type mechanical mechanism is complex, and thus relatively costly to manufacture and sterilize, and Hakky's device may be prone to mechanical breakdown. Moreover, while Hakky's device is designed to coagulate blood before bleeding occurs, some bleeding may still result, particularly from larger vessels, and thus obscure viewing, and provide a possible site for abscess formation.
Other patents showing the general nature of the state of the art in tissue cutting and removing devices are: U.S. Pat. No. 4,694,828 issued to Eichenbaum; U.S. Pat. No. 4,899,733 issued to DeCastro; and U.S. Pat. No. 5,590,200 issued to Tulip.
Approximately 400,000 prostate enlargements are treated surgically in the United States annually. The gold standard for this treatment is Transurethral Resection of Prostate (TURP) and is performed endoscopically using electrocautery loops. Bleeding is a problem following this procedure and the patient requires to be in the hospital with an indwelling catheter for 2-4 days. Frequently, continuous irrigation of the bladder is used to prevent clot retention in such cases. Recently, several alternative treatments have been developed in an attempt to manage these patients on lesser aggressive approaches including balloon dilatations, microwave heating of prostate tissue and pharmacological manipulations. These, however, do not remove the obstructing prostate tissue and lie short in a permanent treatment for BPH. More recently, laser has been used in an attempt to destroy the prostate tissue which then is passed by the patient over the next few weeks opening a channel for free urinary passage thus treating the bladder outlet obstruction thus caused by the enlarged prostate tissue. The drawback of this approach has been the fact that the patient has a suprapubic tube for bladder drainage for 10-14 days until he passes the dead and necrosed prostate tissue. Moreover, the dead tissue passed is no good for histological examination and thus chances of missing an occult prosatic carcinoma is always present.